Multiprotocol label switching (MPLS) is a packet switching technology that allows routing decisions to be based on labels that are prepended to the headers of packets. Such a label represents a path in the network and is used to make forwarding decisions until the corresponding packet reaches its destination. Once the packet reaches its destination, the destination device may “pop” (e.g., remove) the corresponding label from the header of the packet and/or apply another label to the packet, to continue routing the packet throughout the network.
The Resource Reservation Protocol (RSVP) is another networking technology that can be used in various forms of networks, such as MPLS-based networks. More specifically, when used in an MPLS-based network, RSVP provides mechanisms to gather metrics regarding the network (e.g., in terms of bandwidth, jitter, etc.) and, based on the gathered metrics, provide quality of service (QoS) guarantees for certain traffic types by reserving resources. For example, RSVP may be used to reserve network resources for real-time voice and video traffic, to guarantee at least a minimum level of performance. As network conditions can change over time, RSVP also facilitates the reallocation of resources and/or initiation of routing changes in the network. For example, RSVP can be used to enable fast rerouting (RSVP-FRR) in the case of a failure, by switching the traffic to a different network path.
However, approaches such as RSVP require the signaling of explicit tunnels in advance of a failure. Also, the detour path followed by packets is typically misaligned with the capacity planning of the network. Further, RSVP-FRR puts the tunnel head-end in charge of the failover, leading to non-local, signaling-based service recovery instead of local behavior.